Adjusting transitive dependencies of packages slows down unattended-upgrades a lot

[Balint Reczey]

[Impact]

 * Unattended-upgrades tries to mark packages for upgrade and when it fails to do so and falls back to mark adjusting packages to use candidates from allowed origins it can spend a lot of CPU time on packages which are not installable in the end.

[Test Case]

 * Mark an upgradable package from the security pocket as held.
 * Observe u-u adjusting only direct dependencies, instead of doing it recursively.

[Regression Potential]

 * U-u may fail to install updates due to APT not finding a solution without having transitive dependences adjusted. In those cases the update should mark the transitive dependencies which enable the update as direct dependencies.

[Launchpad Janitor (janitor)]

This bug was fixed in the package unattended-upgrades - 1.15

---------------
unattended-upgrades (1.15) unstable; urgency=medium

  [ Tobias Bannert ]
  * update german translation.
    Improved some formulations and punctuation.

  [ Maarten ]
  * Update Dutch translation (Closes: #941672)

  [ Balint Reczey ]
  * autopkgtest: Retry failing downloads a few times
  * test/autopkgtest_kernel_patterns.py: Add debug statements
  * test/autopkgtest_kernel_patterns.py: Use stricter pattern for
    packages to check
  * debian/tests/control: Mark upgrade-between-snapshots as flaky
    (Closes: #941752)
  * Fix whitespace (LP: #1848036)
  * Explain sanity check failures better
  * Adjust only direct dependencies when falling back to adjusting more
    packages.
    Adjusting all transitive dependencies is found to slow down upgrades too
    much when many packages were upgradable but not with adjustments taking
    place. If a package upgrade to be installed by unattended-upgrades requires
    adjusting a transitive but not direct dependency, please add this
    dependency as a direct dependency of the package to unlock the upgrade.
    (Closes: #935653) (LP: #1848357)
  * debian/tests/common-functions: Don't sleep after successful u-u run

 -- Balint Reczey <email address hidden> Tue, 22 Oct 2019 18:48:33 +0200